Transmission system



May 10, 1932.

s CORY TRANSMISSION SYSTEM Filed June 24, 1931 Cam osite si t w m D .m m a J H H u H s & A a M u m u \H M M i H N w i m j? ma a F INVENTOR BY SI (bi :91

ATTORNEY Patented May 10, 1932 UNITED. STATES PATENT/OFFICE SAMUEL I. CORY, OF TOWACO, NEW JERSEY,

ASSIGNOR 'I'O AMERICAN TELEPHONE AND? TELEGRAPH COMPANY, A CORPORATION OF NEW YORK TRANSMISSION SYST M Application filed .Tune 24,

This invention relates to telegraph systems, and more particularly to improved arrangements whereby signals may be originated and received on such systems at a high signaling speed and whereby such high speed signals may be transmitted between stations over lines suitable only for low speed signals.

To distinguish between low speed and high a speed telegraph signals and low speed and high speed telegraph lines for the purpose of this invention, it is pointed out that the speed of the signals may be defined as the number of dots or impulses originated per second. The shortest impulse of a set of message impulses would beutilized to fix the maximum speed of the message signals. The number of these shortest impulses that could be transmitted per second could be termed the speed of the signals or couldbe characterized as the maximum fundamental frequency of the signaling current. p

A telegraph line interconnecting two stations would usually have associated therewith certain selective devices, such as filters or composite sets, and these filters or compositesets might be designed to cut off frequencies above 60 to 7 0 cycles. Accordingly, such a circuit might be suitable for the transmission of telegraph signals having a maximum speed of 60 to 7 O impulses per second or, in other words, for a signaling current below such frequencies. This type of circuit might, for

the purpose of illustrating this invention, be termed a low speed telegraph circuit. Obviously, it may be desirable to originate and receive signals at a speed faster than 60 to 70 impulses per second and this would result in the utilization of a current of a higher frequency. The use of a higher frequency current would not be possible on the type of circuit heretofore termed a low speed circuit because of the cut-off. characteristics of the filsignals, the filters or other devices in the line v V into'a high speed circuit.

1931. '1 Serial m.- 546,625.-

' would ave 17C redesigned toh' h frequency cut-ofi' characteristic so that the line mightbe termed a high speed circuit. Obviously, this would necessitate the reconstruction or redesign of the low speed. circuit- Oneof the primary objects 5f the arrangements of the invention. is to make it possible to utilize the lowspeed circuit without any change therein for the transmissionjof high speed telegraph signals. In the arrangements of the invention this'is accomplished by resolving a series of high speed signals into a plurality, of series of signals ofapproximately half the original frequency,v The signals of this lower frequency may then be transmittedover aplurality of low speed telegraph circuits and may be recombined at the other end'of the line to form the original high speed signals. h c

In the present invention the arrangements for translating the high speed signals into low speed signals for transmission over the lines comprises a circuit arrangementincluding a number of polar relays. 'Other objects-v and features of the invention will appear 1 more fully from. the detailed description stood from the following description, to-g gether with theaccompanying drawingv in the figure, of which the invention is illustrated. r Q o 7 f Inthe drawing is shown a telegraph system in which two stations are interconnected by the lines L and L These lines might be used for both telephone and telegraph purposes and might have included therein selective devices such as filters or the composite setslO,11, 12 and 13. If the lines L and L were used as composited telephone and telegraph lines, the selective devices,

might be designed to hav'e a cut-off frequency of 60 or 0 cycles and,'accordingly, telegraph signals having a greater maximum speed shown a sending circuit 1 with the key K and the relay 17. Controlled by the relay 17 is a circuit including the polar relays A and B. These relays will'resolve the high speed signals originating in the loop circuit 1 into two series of low speed signals fortransmission over the lines L and. L Atthe. receiving and E. These relays will be responsive to the low speed signals transmittedover the lines and will combine these signals into a series of high'speed signals to actuate the sounder Sin the receiving loop circuit 14.

- .The. operation of the arrangements of the invention is as follows: Assume the key K to be closed and the relays A,.B and 17 to be in the marking condition, as" shown. inthe drawing. Assume also that when current flows from terminal 6 to terminal 3 in winding 6-3v of. either relay it moves. the arma ture to the marking contact. The holding windings 2'-7 are poled to effectively hold the relay armature on either the marking or spacing contact. If key K is opened the armature. of relay 17 will be operated to its sp'acing'contact, thereby applying ground to terminal 6 of winding3-6 of relay B. With negative battery connectediover the armature of relay A to terminal 3 of winding 3f'6 of relay B, relay B will be caused to operate to its spacing contact. It will be maintained on its spacing contact by current. flowing from spacing battery'and. armature of relay B through the holding winding" 7+2 to ground. This will apply'positive or spacing battery to conductor 16 and will cause relaysv R to operate" to spacing. This will' transmitspacing current. over the line L and operate the relay D. This will close the loop circuit 14." and operatethe sounder S. If the key K is now closed again, the armature of relay 17 will move toits marking; contact.

This. applies ground to terminal 3 of wind ing63 of relay A and causes the armature of said r'elay'to operate to its spacing contact- This. is because spacing battery isapplied from the armature of relay B to terminal 6 of winding 6+3 of relay A. The armature of relay A will be maintained on its: spacing; contact by thespacing current transmitted through the holding winding 'Z'2 to ground. 'Positive or spacing battery is thereby applied to conductor 15 and oper ates relaysR This will apply spacingw current to the line L and operate relay'E. This will open the loop circuit landrelease the sounder Sat the receiving station. It the key K is again opened, ground 1s again aprelay 17 will be operated toitsmarking con- 7 tact, thereby applying ground to terminal 3 of windlng 6-3 of relay A. Relay A, having p negativebattery connected to the other terend of the system are provided the relays DI minal ofthis winding, will be operated to its marking contact. Thi s will apply marking currentto: conductor 15 and will operate relays R so as to apply marking current to the line L and thereby operate relay E. This operation of relay E will again open the loop circuit 1a and release'the sounder S;

Thus it may be seen thatwhen the key K is opened for the first time, relays B and D will be operated and the sounder S actuated. hen key K is closed again, relays A and B and relays D and IE will beoperated so that the sounder S will not be actuated. When the key K is opened for thesecond' time, relay D will be operated to close the loo circuit 14 and actuate the sounder S1 en key K is closed for the second time, the relays Aand B and the relays D and E will assume the position shown in the drawing and the sounder S will not be actuated and'the fre- I original signaling frequency;

7 The principles. embodied in the arrangements ofthe invention,l wherebylow speed circuits maybe combined to form a high speed circuit, are not limited to the use of two circuits. By varying the relay combinations at the sending'a'nd receiving ends of the transmission system a greater number of circuits may be utilized in the combination ifnecessary. The principles of'the invention may furthermore be utilized in connection with secret transmission systems, since the transmitted signal is not understandable ex cept in the presence of all of its components. The arrangements of the invention may be utilized on lines which do not include filters or composite setsif the frequency characteris- V tics of the lines themselvesmake it desirable.

The arrangements of the invention are furthermore applicable to other types oftel'egraph systems from those illustrated, such for'example as carrier telegraph and radio systems.

hile the invention has been disclosed as embodied in certain specific forms which are deemed desirable, it is understood that it is capable of embodiment in many and other widely varied forms without departing from the spirit of the invention as defined by the appended claims.

What is claimed is:

l. The combination of a high speed telegraph circuit with two low speed telegraph circuits, a translating device for resolving the original high speed signals into two series of low speed signals for transmission over said. low speed circuits, said translating device comprising two polar relays for controlling high speed signals into two series of low speed signals for transmission over said low speed circuits, said translating device consisting of two polar relays each having single armatures for directly applying signals to said lowspeed'circuits, and operating circuits for-said relays controlled by switching means and completed over said single armatures and said switching means. 7

In testimony whereof, I have signed my name to this specification this 22nd day of June 19.31; p o l SAMUEL I. CORY.

said low speed circuits, saidtranslating device 7 comprising two polar relays for controlling the speed of application of signals to said low speed circuits and controlled by the high speed signals, each of said polar relays having armatures associated with said low speed circuits and contacts with marking and spacing battery connected thereto, one of said relays having an operating winding connected to the armature of the other relay and so poled that the application of marking battery thereto will cause it to moveits armature to the spacing contact, the second of said relays having an operating winding connected to the armature of the first relay and so poled that the application of spacing battery thereto will cause it to move its armature tospacing, and holding windings for each of said relays connected to their own relay armatures.

3. The combination of a high speed telegraph circuit with two low speed telegraph circuits, a translating device for resolving the original high speedsignals into two series of low speed signals for transmission over said low speed circuits, said translating device comprising two polar relays controlled by the high speed signals for controlling the application of signals to said low speed circuits whereby the frequency of the signals in each of said low speed circuits will be approximately one half the frequency of the original high speed signals, each of said polar relays having operating windings oppositely poled with respect to each other and connected to the armatures of the other of said relays, and each of said polar relays having holding windings connected to their own relay armatures.

4E. The combination of a high speed telegraph circuit with two low speed circuits, a translating device for resolving the original 

